Optical sensor

Abstract

Provided is an optical sensor which makes it possible to acquire multiple types of information in a short period of time via multiple wavelengths.　This optical sensor comprises: a light reception unit which is equipped with multiple pixels arranged in a plane and which is for receiving light from an object to be measured; an interposer which has multiple through-holes formed therein and which is disposed above the light reception unit so as to have one or more of the through-holes overlap each of the pixels of the light reception unit; a first wavelength selection unit which causes light in a first wavelength band to transmit therethrough and which is provided so as to overlap through-holes belonging to a first group among the aforementioned multiple through-holes; and a second wavelength selection unit which causes light in a second wavelength band to transmit therethrough and which is disposed so as to overlap through-holes belonging to a second group which is different from the first group, among the aforementioned through-holes.

Description

Optical Sensor

[0001] The present invention relates to an optical sensor.

[0002] An optical sensor can obtain predetermined information by irradiating a measurement object with light in a specific wavelength band and sensing the reflected light or transmitted light from the measurement object. For example, an optical sensor can obtain fingerprint information by irradiating a finger with visible light and sensing the reflected light or transmitted light. An optical sensor can also obtain vein information by irradiating a finger with near-infrared light and sensing the transmitted light.

[0003] Furthermore, as a method for extracting only parallel light from scattered light, there is a method using a collimator (see Patent Document 1 below).

[0004] International Publication No. 2019 / 167145

[0005] Optical sensors can acquire multiple types of information about an object by irradiating the object with light of multiple wavelength bands in sequence at intervals and sensing the reflected light and transmitted light from the object, respectively. However, doing so has the problem of taking a long time to acquire all of the multiple types of information.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an optical sensor that can acquire multiple types of information using multiple wavelengths in a short period of time.

[0007] An optical sensor according to one aspect of the present disclosure includes: a light receiving unit having a plurality of pixels arranged on a plane and receiving light from a measurement object; an interposer having a plurality of through holes and arranged above the light receiving unit such that one or more of the through holes overlap with each of the pixels; a first wavelength selecting unit that transmits light of a first wavelength band and is arranged to overlap with each of the plurality of through holes that belong to a first group; and a second wavelength selecting unit that transmits light of a second wavelength band and is arranged to overlap with each of the plurality of through holes that belong to a second group different from the first group.

[0008] According to the present disclosure, multiple types of information can be obtained using multiple wavelengths in a short period of time.

[0009] 1 is a plan view showing an outline of an optical sensor. FIG. 2 is a block diagram showing an example of the configuration of an optical sensor. FIG. 3 is a circuit diagram showing an optical sensor. FIG. 4 is a circuit diagram of a part of a detection region. FIG. 5 is a partial cross-sectional view showing a cross section taken along line V-V in FIG. 1. FIG. 6 is a schematic diagram showing a cross section and a top surface of an optical sensor according to a first embodiment. FIG. 7 is a diagram showing a method for manufacturing an interposer according to a modified example of the first embodiment. FIG. 8 is a schematic diagram showing a cross section and a top surface of an optical sensor according to a modified example of the first embodiment. FIG. 9 is a diagram showing a change in sensor output over time. FIG. 10 is a schematic diagram showing a cross section and a top surface of an optical sensor according to a second embodiment. FIG. 11 is a diagram showing a method for manufacturing an interposer according to the second embodiment. FIG. 12 is a schematic diagram showing a cross section and a top surface of an optical sensor according to a third embodiment.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the present invention, and the present invention should not be construed as being limited to the description of the embodiments exemplified below.

[0011] In order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In this specification and each drawing, elements having the same functions as those explained in the previous drawings may be assigned the same reference numerals, and duplicate explanations may be omitted.

[0012] Furthermore, in the detailed description of the present invention, when defining the positional relationship between a certain component and another component, "above" and "below" do not only mean being located directly above or directly below a certain component, but also include cases where there are other components interposed between them, unless otherwise specified.

[0013] 1 is a plan view showing an outline of an optical sensor 1 according to a first embodiment of the present invention. As shown in Fig. 1, the optical sensor 1 has a resin substrate 100, a light receiving section 10, a gate line driving circuit 15, a signal line selection circuit 16, a control circuit 26, a power supply circuit 28, a detection circuit 48, a flexible printed circuit board 300, and a control board 400.

[0014] A control board 400 is electrically connected to the resin substrate 100 via a flexible printed circuit board 300. A detection circuit 48 is provided on the flexible printed circuit board 300. The control board 400 is provided with a control circuit 26 and a power supply circuit 28. The control circuit 26 supplies control signals to the light receiving unit 10, the gate line driving circuit 15, and the signal line selection circuit 16 to control the detection operation of the light receiving unit 10. The detection circuit 48 and the control circuit 26 are, for example, an integrated circuit (IC) or a field programmable gate array (FPGA). The power supply circuit 28 supplies a power supply voltage to the light receiving unit 10, the gate line driving circuit 15, and the signal line selection circuit 16.

[0015] The resin substrate 100 has a detection area DA and a frame area PA. The detection area DA is an area where the light receiving unit 10 is provided. The frame area PA is an area outside the detection area DA, and is an area where the light receiving unit 10 is not provided.

[0016] The frame area PA has a bending area BA and a terminal area TA. The bending area BA and the terminal area TA are provided at one end of the frame area PA. Wiring connected to the detection area DA is arranged in the bending area BA and the terminal area TA. The resin substrate 100 and the flexible printed circuit board 300 are connected in the terminal area TA.

[0017] The light receiving unit 10 includes a plurality of pixels PX arranged on a plane and receives light from a measurement target. The pixels PX are arranged in a matrix in the detection area DA. Each pixel PX includes a light sensor 30 (see FIG. 4 ), which is a photodiode, and outputs an electrical signal corresponding to the light incident thereon. Each pixel PX outputs the electrical signal corresponding to the light incident thereon as a first detection signal Vdet to the signal line selection circuit 16. Each pixel PX performs detection in accordance with a gate drive signal Vgcl supplied from the gate line drive circuit 15.

[0018] The gate line driving circuit 15 and the signal line selection circuit 16 are provided in the frame region PA. Specifically, the gate line driving circuit 15 is provided in a region of the frame region PA extending in the extension direction of the signal lines SGL (second direction Dy). The signal line selection circuit 16 is provided in a region of the frame region PA extending in the extension direction of the gate lines GCL (first direction Dx), and is provided between the light receiving unit 10 and the bending region BA.

[0019] 2 is a block diagram showing an example of the configuration of the optical sensor 1 according to an embodiment of the present invention. As shown in Fig. 2, the optical sensor 1 further includes a detection control unit 11 and a detection unit 40. Some or all of the functions of the detection control unit 11 are included in a control circuit 26. In addition, some or all of the functions of the detection unit 40 are included in the control circuit 26.

[0020] The detection control unit 11 is a circuit that supplies control signals to the gate line driving circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control unit 11 supplies various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST, to the gate line driving circuit 15. The detection control unit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16.

[0021] The gate line driving circuit 15 is a circuit that drives the gate lines GCL based on various control signals. The gate line driving circuit 15 sequentially or simultaneously selects multiple gate lines GCL and supplies a gate driving signal Vgcl to the selected gate lines GCL. In this way, the gate line driving circuit 15 selects the pixels PX connected to the gate lines GCL.

[0022] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of signal lines SGL. The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected signal line SGL to the detection circuit 48 based on a selection signal ASW supplied from the detection control unit 11. As a result, the signal line selection circuit 16 outputs the first detection signal Vdet of the pixel PX to the detection unit 40.

[0023] The detection unit 40 includes a signal processing unit 44, a storage unit 45, a coordinate extraction unit 46, a detection timing control unit 47, and a detection circuit 48. The detection timing control unit 47 controls the signal processing unit 44, the coordinate extraction unit 46, and the detection circuit 48 based on a control signal supplied from the detection control unit 11 so that they operate in synchronization with each other.

[0024] The detection circuit 48 is, for example, an analog front end (AFE) circuit. The detection circuit 48 is a signal processing circuit that has at least the functions of a detection signal amplifier 42 and an A / D converter 43. The detection signal amplifier 42 amplifies the first detection signal Vdet. The A / D converter 43 converts the analog signal output from the detection signal amplifier 42 into a digital signal.

[0025] The signal processing unit 44 is a logic circuit that detects a predetermined physical quantity input to the light receiving unit 10 based on the output signal of the detection circuit 48. When the finger Fg comes into contact with or close to the detection surface, the signal processing unit 44 can detect unevenness on the surface of the finger Fg or palm based on the signal from the detection circuit 48. The signal processing unit 44 can also detect information about the living body based on the signal from the detection circuit 48. The information about the living body includes, for example, an image of the blood vessels of the finger Fg or palm, a pulse wave, a pulse rate, and blood oxygen saturation. The signal processing unit 44 also calculates a signal ΔV that is the difference between the first detection signal Vdet and the second detection signal Vdet-R.

[0026] The storage unit 45 temporarily stores the signals calculated by the signal processing unit 44. The storage unit 45 also stores information relating to the past first detection signal Vdet, second detection signal Vdet-R, and difference signal ΔV. The storage unit 45 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0027] The coordinate extraction unit 46 is a logic circuit that calculates the detected coordinates of the unevenness of the surface of the finger Fg or the like when the signal processing unit 44 detects contact or proximity of the finger Fg. The coordinate extraction unit 46 is also a logic circuit that calculates the detected coordinates of the blood vessels of the finger Fg or the palm. The coordinate extraction unit 46 combines the first detection signals Vdet output from each optical sensor 30 of the light receiving unit 10 to generate two-dimensional information that indicates the shape of the unevenness of the surface of the finger Fg or the like. Note that the coordinate extraction unit 46 may output the first detection signal Vdet and the second detection signal Vdet-R as the sensor output Vo without calculating the detection coordinates.

[0028] Next, an example of the circuit configuration and operation of the optical sensor 1 will be described. Fig. 3 is a circuit diagram showing the optical sensor. Fig. 4 is a circuit diagram of a part of the detection area. Fig. 4 also shows the circuit configuration of the detection circuit 48.

[0029] 3, the light receiving section 10 has a plurality of partial detection areas PAA arranged in a matrix. An optical sensor 30 is provided in each of the partial detection areas PAA.

[0030] The gate lines GCL extend in the first direction Dx and are connected to a plurality of partial detection areas PAA arranged in the first direction Dx. Furthermore, a plurality of gate lines GCL(1), GCL(2), ..., GCL(8) are arranged in the second direction Dy and are each connected to the gate line driving circuit 15. In the following description, when it is not necessary to distinguish between the plurality of gate lines GCL(1), GCL(2), ..., GCL(8), they will simply be referred to as gate lines GCL. Although FIG. 3 shows eight gate lines GCL for ease of explanation, this is merely an example, and M gate lines GCL (where M is 8 or more, e.g., M=256) may be arranged.

[0031] The signal line SGL extends in the second direction Dy and is connected to the optical sensors 30 in the multiple partial detection areas PAA arranged in the second direction Dy. The multiple signal lines SGL(1), SGL(2), ..., SGL(12) are arranged in the first direction Dx and are each connected to the signal line selection circuit 16 and the reset circuit 17. In the following description, when it is not necessary to distinguish between the multiple signal lines SGL(1), SGL(2), ..., SGL(12), they will be simply referred to as signal lines SGL.

[0032] For ease of understanding, 12 signal lines SGL are shown, but this is merely an example, and N signal lines SGL (N is 12 or more, for example, N=252) may be arranged. The sensor resolution is, for example, 508 dpi (dots per inch), and the number of cells is 252×256. In FIG. 3 , the light receiving unit 10 is provided between the signal line selection circuit 16 and the reset circuit 17. However, the present invention is not limited to this, and the signal line selection circuit 16 and the reset circuit 17 may be connected to ends of the signal lines SGL facing in the same direction.

[0033] The gate line drive circuit 15 receives various control signals, such as a start signal STV, a clock signal CK, and a reset signal RST1, from the detection control unit 11. The gate line drive circuit 15 sequentially selects multiple gate lines GCL(1), GCL(2), ..., GCL(8) in a time-division manner based on the various control signals. The gate line drive circuit 15 supplies a gate drive signal Vgcl to the selected gate line GCL. As a result, the gate drive signal Vgcl is supplied to multiple first switching elements Tr connected to the gate line GCL, and multiple partial detection areas PAA arranged in the first direction Dx are selected as detection targets.

[0034] The gate line driving circuit 15 may perform different driving for each detection mode of a fingerprint and a plurality of different pieces of biological information (pulse wave, pulse, blood vessel image, blood oxygen saturation, etc.) For example, the gate line driving circuit 15 may drive a bundle of a plurality of gate lines GCL.

[0035] Specifically, the gate line driving circuit 15 may simultaneously select a predetermined number of gate lines GCL from among the gate lines GCL(1), GCL(2), ..., GCL(8) based on a control signal. For example, the gate line driving circuit 15 simultaneously selects six gate lines GCL(1) to GCL(6) and supplies the gate driving signal Vgcl to the gate lines. The gate line driving circuit 15 supplies the gate driving signal Vgcl to a plurality of first switching elements Tr via the six selected gate lines GCL. As a result, group areas PAG1 and PAG2, each including a plurality of partial detection areas PAA arranged in the first direction Dx and the second direction Dy, are selected as detection targets. The gate line driving circuit 15 drives a predetermined number of gate lines GCL together and sequentially supplies the gate driving signal Vgcl to each of the predetermined number of gate lines GCL. Hereinafter, when the positions of different group areas, such as the group areas PAG1 and PAG2, are not particularly distinguished from one another, they will be referred to as group areas PAG.

[0036] The signal line selection circuit 16 has a plurality of selection signal lines Lsel, a plurality of output signal lines Lout, and a second switching element TrS. The plurality of second switching elements TrS are provided corresponding to the plurality of signal lines SGL, respectively. The six signal lines SGL(1), SGL(2), ..., SGL(6) are connected to a common output signal line Lout1. The six signal lines SGL(7), SGL(8), ..., SGL(12) are connected to a common output signal line Lout2. The output signal lines Lout1 and Lout2 are each connected to a detection circuit 48.

[0037] Here, the signal lines SGL(1), SGL(2), ..., SGL(6) are defined as a first signal line block, and the signal lines SGL(7), SGL(8), ..., SGL(12) are defined as a second signal line block. The multiple selection signal lines Lsel are connected to the gates of the second switching elements TrS included in one signal line block. Furthermore, one selection signal line Lsel is connected to the gates of the second switching elements TrS of multiple signal line blocks.

[0038] Specifically, the selection signal lines Lsel1, Lsel2, ..., Lsel6 are connected to the second switching elements TrS corresponding to the signal lines SGL(1), SGL(2), ..., SGL(6), respectively. The selection signal line Lsel1 is connected to the second switching element TrS corresponding to the signal line SGL(1) and the second switching element TrS corresponding to the signal line SGL(7). The selection signal line Lsel2 is connected to the second switching element TrS corresponding to the signal line SGL(2) and the second switching element TrS corresponding to the signal line SGL(8).

[0039] The detection control unit 11 sequentially supplies the selection signal ASW to the selection signal line Lsel. As a result, the signal line selection circuit 16 sequentially selects the signal lines SGL in one signal line block in a time-division manner through the operation of the second switching element TrS. The signal line selection circuit 16 also selects one signal line SGL from each of the multiple signal line blocks. This configuration allows the optical sensor 1 to reduce the number of integrated circuits (ICs) including the detection circuit 48 or the number of IC terminals.

[0040] The signal line selection circuit 16 may bundle multiple signal lines SGL and connect them to the detection circuit 48. Specifically, the detection control unit 11 simultaneously supplies selection signals ASW to the selection signal lines Lsel. As a result, the signal line selection circuit 16 selects multiple signal lines SGL (e.g., six signal lines SGL) in one signal line block through the operation of the second switching element TrS and connects the multiple signal lines SGL to the detection circuit 48. As a result, signals detected in each group area PAG are output to the detection circuit 48. In this case, signals from multiple partial detection areas PAA (optical sensors 30) are integrated for each group area PAG and output to the detection circuit 48.

[0041] By performing detection for each group area PAG through the operation of the gate line drive circuit 15 and the signal line selection circuit 16, the strength of the first detection signal Vdet obtained in one detection is improved, thereby improving sensor sensitivity. Furthermore, the time required for detection can be shortened. Therefore, the optical sensor 1 can repeatedly perform detection in a short period of time, improving the S / N ratio and enabling accurate detection of temporal changes in information related to a living body, such as pulse waves.

[0042] The reset circuit 17 has a reference signal line Lvr, a reset signal line Lrst, and third switching elements TrR. The third switching elements TrR are provided corresponding to the multiple signal lines SGL. The reference signal line Lvr is connected to either the sources or drains of the multiple third switching elements TrR. The reset signal line Lrst is connected to the gates of the multiple third switching elements TrR.

[0043] The detection control unit 11 supplies a reset signal RST2 to the reset signal line Lrst. This turns on the multiple third switching elements TrR, and electrically connects the multiple signal lines SGL to the reference signal line Lvr. The power supply circuit 28 supplies a reference signal COM to the reference signal line Lvr. This supplies the reference signal COM to the additional capacitances Cad (see FIG. 4) included in the multiple partial detection areas PAA.

[0044] As shown in FIG. 4 , the partial detection area PAA includes a photosensor 30, an additional capacitance Cad, and a first switching element Tr. FIG. 4 shows two gate lines GCL(m) and GCL(m+1) aligned in the second direction Dy among the multiple gate lines GCL. Also shown are two signal lines SGL(n) and SGL(n+1) aligned in the first direction Dx among the multiple signal lines SGL. The partial detection area PAA is an area surrounded by the gate lines GCL and the signal lines SGL. The first switching element Tr is provided corresponding to the photosensor 30. The first switching element Tr is configured by a thin-film transistor TFT (see FIG. 5 ), and in this example, is configured by an n-channel MOS (Metal Oxide Semiconductor) TFT (Thin Film Transistor).

[0045] The gates of the first switching elements Tr belonging to the partial detection areas PAA aligned in the first direction Dx are connected to the gate line GCL. The sources of the first switching elements Tr belonging to the partial detection areas PAA aligned in the second direction Dy are connected to the signal line SGL. The drains of the first switching elements Tr are connected to the cathodes of the optical sensors 30 and the additional capacitances Cad.

[0046] A sensor power supply signal VDDSNS is supplied to the anode of the optical sensor 30 from the power supply circuit 28. Furthermore, a reference signal COM, which becomes the initial potential of the signal line SGL and the additional capacitance Cad, is supplied from the power supply circuit 28 to the signal line SGL and the additional capacitance Cad.

[0047] When light is irradiated onto the partial detection area PAA, a current corresponding to the amount of light flows through the optical sensor 30, causing charge to accumulate in the additional capacitance Cad. When the first switching element Tr is turned on, a current corresponding to the charge accumulated in the additional capacitance Cad flows through the signal line SGL. The signal line SGL is connected to the detection circuit 48 via the second switching element TrS of the signal line selection circuit 16. This allows the optical sensor 1 to detect a signal corresponding to the amount of light irradiated onto the optical sensor 30 for each partial detection area PAA or for each group area PAG.

[0048] The detection signal amplifier 42 of the detection circuit 48 converts fluctuations in current supplied from the signal line SGL into fluctuations in voltage and amplifies the voltage. A reference potential Vref having a fixed potential is input to the non-inverting input terminal (+) of the detection signal amplifier 42. When the output switch SSW is in the ON state, the signal line SGL is connected to the inverting input terminal (-). A signal identical to the reference signal COM is input as the reference potential Vref. The detection signal amplifier 42 also has a capacitance element Cb and a reset switch RSW. When signal readout for one row is completed, the reset switch RSW is turned on, resetting the charge in the capacitance element Cb.

[0049] Next, the cross-sectional configuration of the optical sensor 1 will be described. FIG. 5 is a partial cross-sectional view showing a cross section taken along line V-V in FIG. 1 in the first embodiment. Note that the interposer 600 (described below) is omitted from FIG. 5. FIG. 5 also shows a cross-sectional view of a portion of the detection area DA and a portion of the frame area PA. As described above, the detection area DA has a plurality of pixels PX, and the frame area PA has a bending area BA and a terminal area TA. Each pixel PX has a corresponding lower electrode 210 and a corresponding thin-film transistor TFT. Furthermore, the circuit layer CL has a barrier inorganic film 110 to an inorganic insulating film 180, and the organic photoelectric conversion layer OPL has a lower electrode 210 to an upper electrode 230.

[0050] 5 shows a cross section in the second direction Dy, but when the detection area DA is cut in the first direction Dy, a cross-sectional structure similar to that in FIG. 4 is observed. In addition, in FIG. 5, hatching of some layers is omitted to make the cross-sectional structure easier to see.

[0051] From here on, the laminated structure from the resin substrate 100 to the sealing film 260 will be described in order from the bottom up. First, the circuit layer CL provided on the resin substrate 100 will be described.

[0052] A barrier inorganic film 110 is laminated on a resin substrate 100. The resin substrate 100 is formed of polyimide. However, the resin substrate 100 may be formed using other resin materials as long as the substrate is sufficiently flexible for use as a sheet-type optical sensor. Meanwhile, the barrier inorganic film 110 has a three-layer laminate structure consisting of a first inorganic film 111 (e.g., a silicon oxide film), a second inorganic film 112 (e.g., a silicon nitride film), and a third inorganic film 113 (a silicon oxide film). The first inorganic film 111 is provided to improve adhesion to the substrate, the second inorganic film 112 serves as a blocking film against external moisture and impurities, and the third inorganic film 113 serves as a blocking film to prevent hydrogen atoms contained in the second inorganic film 112 from diffusing toward the semiconductor layer 131. However, the structure is not limited to this. Further laminates may be provided, or a single layer or two-layer laminate may be used.

[0053] The additional film 120 may be formed in accordance with the location where the thin film transistor TFT (described later) is to be formed. The additional film 120 can suppress changes in the characteristics of the thin film transistor TFT due to light intrusion from the back surface of the channel of the thin film transistor TFT, or can provide a back-gate effect to the thin film transistor TFT by forming the additional film 120 from a conductive material and applying a predetermined potential. Here, after forming the first inorganic film 111, the additional film 120 is formed in an island shape in accordance with the location where the thin film transistor TFT is to be formed, and then the second inorganic film 112 and the third inorganic film 113 are laminated to form the additional film 120 in the barrier inorganic film 110. However, this is not limited thereto, and the additional film 120 may be formed first on the resin substrate 100, and then the barrier inorganic film 110 may be formed.

[0054] A thin-film transistor TFT is formed on the barrier inorganic film 110 for each pixel PX. The thin-film transistor TFT includes a semiconductor layer 131, a gate electrode 132, a source electrode 133, and a drain electrode 134. While only an N-channel transistor is shown here using a polysilicon thin-film transistor as an example, a P-channel transistor may also be formed at the same time. The semiconductor layer 131 of the thin-film transistor TFT has a structure in which a low-concentration impurity region or an intrinsic semiconductor region is provided between the channel region and the source / drain regions. The gate electrode 132 is the portion where the gate line GCL is electrically connected to the semiconductor layer 131 in each pixel PX. Similarly, the source electrode 133 is the portion where the signal line SGL is electrically connected to the semiconductor layer 131 in each pixel PX.

[0055] A gate insulating film 140 is provided between the semiconductor layer 131 and the gate electrode 132. Here, a silicon oxide film is used as the gate insulating film 140. The gate electrode 132 is part of a first wiring layer W1 formed from MoW. In addition to the gate electrode 132, the first wiring layer W1 has a first storage capacitance line CsL1. A part of the storage capacitance Cs is formed between the first storage capacitance line CsL1 and the semiconductor layer 131 (source / drain region) via the gate insulating film 140.

[0056] An interlayer insulating film 150 is formed on the gate electrode 132. The interlayer insulating film 150 has a structure in which a silicon nitride film and a silicon oxide film are stacked. In the area corresponding to the bent region BA, the barrier inorganic film 110 to the interlayer insulating film 150 are removed by patterning. In the area corresponding to the bent region BA, the polyimide constituting the resin substrate 100 is exposed. When the barrier inorganic film 110 is removed by patterning, the polyimide surface may be partially eroded, resulting in a reduction in film thickness.

[0057] Wiring patterns are formed below the step portions at the ends of the interlayer insulating film 150 and the step portions at the ends of the barrier inorganic film 110. The lead wiring RW passes over the wiring patterns when crossing the step portions. For example, a gate electrode 132 is present between the interlayer insulating film 150 and the barrier inorganic film 110, and for example, an additional film 120 is present between the barrier inorganic film 110 and the resin substrate 100, so these layers are used to form the wiring patterns.

[0058] A second wiring layer W2 including portions that will become the source electrode 133, the drain electrode 134, and the routing wiring RW is formed on the interlayer insulating film 150. A three-layer stacked structure of Ti, Al, and Ti is employed here. Another portion of the storage capacitor Cs is formed by a first storage capacitance line CsL1 (part of the first wiring layer W1) and a second storage capacitance line CsL2 (part of the second wiring layer W2) via the interlayer insulating film 150. The routing wiring RW extends to a terminal area TA via a bent area BA, forming a terminal portion T for connecting a flexible printed circuit board 300 or the like.

[0059] The lead wiring RW is formed to cross the bent region BA and reach the terminal portion T, and therefore crosses the step portion of the interlayer insulating film 150 and the barrier inorganic film 110. As described above, a wiring pattern is formed in the step portion using, for example, the additional film 120. Therefore, even if the lead wiring RW is disconnected at the recess of the step, electrical connection can be maintained by contacting the wiring pattern.

[0060] A planarization film 160 is provided so as to cover the source electrode 133, the drain electrode 134, and the interlayer insulating film 150. The planarization film 160 is made of a resin such as photosensitive acrylic, as this has superior surface flatness compared to inorganic insulating materials formed by CVD (Chemical Vapor Deposition), etc. The planarization film 160 is removed in the pixel contact portion 170, the upper electrode contact portion 171, the bent region BA, and the terminal region TA.

[0061] A transparent conductive film 190 made of indium tin oxide (ITO) is formed for each pixel PX on the planarization film 160. The transparent conductive film 190 includes a first transparent conductive film 191 and a second transparent conductive film 192 that are separated from each other.

[0062] The first transparent conductive film 191 is electrically connected to the second wiring layer W2, the surface of which is exposed by removing the planarization film 160, in the pixel contact portion 170. On the other hand, the second transparent conductive film 192 is provided below the lower electrode 210 (further below the inorganic insulating film 180), which will be described later, and next to the pixel contact portion 170. Then, an inorganic insulating film 180 (silicon nitride film) is provided on the transparent conductive film 190 and the planarization film 160 so as to cover the first transparent conductive film 191 except for the opening of the pixel contact portion 170.

[0063] The second transparent conductive film 192, the inorganic insulating film 180, and the lower electrode 210 overlap in plan view, and form an additional capacitance Cad.

[0064] The transparent conductive film 190 may also be formed on the surface of the terminal portion T to form a third transparent conductive film 193. The third transparent conductive film 193 formed on the surface of the terminal portion T may be provided one of the purposes of protecting the exposed wiring portion from damage in a process subsequent to the formation of the third transparent conductive film 193.

[0065] A lower electrode 210 is provided for each pixel PX on the inorganic insulating film 180 so as to be electrically connected to the drain electrode 134 through an opening in the inorganic insulating film 180 in the pixel contact portion 170. The lower electrode 210 is formed as a reflective electrode and has a three-layer laminate structure of an indium zinc oxide film, an Ag film, and an indium zinc oxide film. Here, an indium tin oxide film may be used instead of the indium zinc oxide film. The lower electrode 210 extends laterally from the pixel contact portion 170 and reaches above the thin film transistor TFT.

[0066] An organic material layer 220 is provided on the lower electrode 210. The organic material layer 220 includes, from bottom to top, a lower carrier transport layer 221, an organic light-receiving layer 222, and an upper carrier transport layer 223. When a front-illuminated structure is adopted, the lower carrier transport layer 221 serves as a hole transport layer, and the upper carrier transport layer 223 serves as an electron transport layer. However, when a back-illuminated structure is adopted, the lower carrier transport layer 221 serves as an electron transport layer, and the upper carrier transport layer 223 serves as a hole transport layer. The organic light-receiving layer 222 may be formed by vapor deposition or by coating on a solvent dispersion. Here, it is formed solidly over the entire surface covering the detection area DA, but this is not limited to this.

[0067] An upper electrode 230 is formed on the organic material layer 220 in common with each pixel PX. When a front-illuminated structure is employed, the upper electrode 230 must be transparent. Here, PEDOT:PSS is formed on the surface in contact with the organic material layer 220, and then the upper electrode 230 is formed as a thin film that allows incident light to pass through using a metal material such as Ag or Al. The upper electrode 230 is formed from the organic material layer 220 in the detection area DA to the upper electrode contact portion 171 in the frame area PA. The upper electrode 230 is then electrically connected to the routing wiring RW of the second wiring layer W2 at the upper electrode contact portion 171 and ultimately led out to the terminal portion T.

[0068] A sealing film 260 is formed on the upper electrode 230. One of the functions of the sealing film 260 is to protect the organic material layer 220 from moisture and other elements that may enter from the outside, and a high level of gas barrier property is required. Here, the laminated structure including the silicon nitride film is a laminated structure of a silicon nitride film, an organic resin, and a silicon nitride film. A silicon oxide film or an amorphous silicon layer may be provided between the silicon nitride film and the organic resin to improve adhesion. However, since this is a film provided on the light-receiving surface side, a material that does not have an effect such as absorption of light of the wavelength to be detected is preferred.

[0069] If necessary, a cover member 1300 (see FIG. 13) may be provided on the sealing film 260. In this case, an adhesive film, which is a filler made of resin or the like, may be disposed between the cover glass and the sealing film 260 to fill the gap between them. The cover member 1300 is preferably made of a material that does not absorb light of the wavelength to be detected.

[0070] Next, the interposer 600 will be described. FIG. 6(a) is a schematic diagram showing a cross section of the optical sensor 1 according to the first embodiment. FIG. 6(b) is a schematic diagram showing the top surface of the optical sensor 1 according to the first embodiment. Note that FIGS. 6(a) and 6(b) are views of an extracted pixel region of 4 columns and 6 rows of the light receiving unit shown in FIG. 3. As shown in FIGS. 6(a) and 6(b), the optical sensor 1 has a sensor unit 602, an interposer 600, a first adhesive film 604, and a second adhesive film 606.

[0071] The sensor unit 602 includes the resin substrate 100 to the sealing film 260 shown in Fig. 5. In Fig. 6(a) and Fig. 6(b), the layers shown in Fig. 5 are omitted, and only the pixel PX is shown so that the positional relationship between the through-hole 610 of the interposer 600 and the pixel PX can be understood.

[0072] The first adhesive film 604 and the second adhesive film 606 are, for example, optical clear adhesive (OCA). The first adhesive film 604 is provided on the sealing film 260 and covers the sealing film 260. The second adhesive film 606 is disposed above the interposer 600 and covers the interposer 600. The first adhesive film 604 and the second adhesive film 606 are both made of a material that transmits the entire wavelength range of visible light and near-infrared light.

[0073] The interposer 600 has a plurality of through holes 610 and is disposed above the light receiving section such that one or more of the through holes 610 overlap each pixel PX. Specifically, the interposer 600 has, for example, a light shielding section 608, a plurality of through holes 610, a first wavelength selecting section 612, and a second wavelength selecting section 614. Specifically, the light shielding section 608 is made of a material that does not transmit visible light. The thickness of the light shielding section 608 is, for example, 125 μm.

[0074] The multiple through holes 610 are holes that penetrate the interposer 600. The opening size of each through hole 610 is, for example, 30 μm to 50 μm. The spacing between adjacent through holes 610 is, for example, 75 μm to 100 μm. Here, it is desirable that the opening size d2 on the light receiving section side of the through hole 610 (i.e., the first adhesive film 604 side) be smaller than the opening size d1 on the opposite side (i.e., the second adhesive film 606 side). In addition, the aspect ratio obtained by dividing the thickness t of the interposer 600 by the average value of the opening size d2 on the first adhesive film 604 side and the opening size d1 on the second adhesive film 606 side is 1 or greater, preferably 2 to 20.

[0075] The plurality of through holes 610 are arranged in a matrix, including those belonging to a first group and those belonging to a second group, and the first and second groups are arranged side by side in a plane. Specifically, the plurality of through holes 610 are arranged one above each pixel PX arranged in a matrix, as shown in Figure 6(b), and the through holes 610 in odd-numbered columns belong to the first group, and the through holes 610 in even-numbered columns belong to the second group.

[0076] The first wavelength selecting portion 612 transmits light in a first wavelength band and is provided so as to overlap with the through holes 610 belonging to a first group. The second wavelength selecting portion 614 transmits light in a second wavelength band and is provided so as to overlap with the through holes 610 belonging to a second group different from the first group. Specifically, for example, the first wavelength selecting portion 612 and the second wavelength selecting portion 614 are resins disposed inside the through holes 610. The first wavelength selecting portion 612 is a resin that fills the through holes 610 belonging to the first group and transmits only light in a first wavelength band (e.g., 640 nm to 680 nm centered at 660 nm). The second wavelength selecting portion 614 is a resin that fills the through holes 610 belonging to the second group and transmits only light in a second wavelength band (e.g., 830 nm to 870 nm centered at 850 nm).

[0077] Next, a manufacturing method of the interposer 600 will be described with reference to FIG. 7. First, a light-shielding film corresponding to the size of the detection area DA is prepared. Then, when the light-shielding film is placed on the sensor unit 602, through-holes 610 are formed in the light-shielding film at positions that overlap with each pixel PX. At this time, the through-holes 610 belonging to the first group and the through-holes 610 belonging to the second group are formed simultaneously.

[0078] Next, the through holes 610 belonging to the first group are filled with a resin that will become the first wavelength selection portion 612. For example, the through holes 610 belonging to the first group are filled with a resin that transmits only light in a first wavelength band (for example, 640 nm to 680 nm with 660 nm as the center).

[0079] Next, the through holes 610 belonging to the second group are filled with a resin that will become the second wavelength selection portion 614. For example, the through holes 610 belonging to the second group are filled with a resin that transmits only light in a second wavelength band (for example, 830 nm to 870 nm with 850 nm as the center). Note that the steps of filling the first wavelength selection portion 612 and the second wavelength selection portion 614 may be performed in any order.

[0080] 8 , after the through holes 610 belonging to the first group and the through holes 610 belonging to the second group are formed, the through holes 610 belonging to the second group are filled with a resin (second wavelength selecting portion 614) that transmits magenta light up to about half the height of the through holes 610. Next, the through holes 610 belonging to the first and second groups are filled with a resin (first wavelength selecting portion 612) that transmits yellow light up to the upper limit of the height of the through holes 610.

[0081] By this process, the through-holes 610 belonging to the second group are filled with a combination of a resin that transmits magenta light and a resin that transmits yellow light, and as a result, the through-holes 610 belonging to the second group transmit only red light.

[0082] Although the above description has been given of the case where the through holes 610 in odd-numbered columns belong to the first group and the through holes 610 in even-numbered columns belong to the second group, the present disclosure is not limited to this. For example, as shown in Figures 9(a) and 9(b), the first group and the second group may be classified into groups of multiple columns (four columns in the figures).

[0083] The number of groups is not limited to two and may be three or more. For example, as shown in FIGS. 9( a) and 9(b), a first group of through-holes 610, a second group of through-holes 610, and a third group of through-holes 610 may be provided. The first group of through-holes 610 is filled with a first wavelength-selecting section 612, the second group of through-holes 610 is filled with a second wavelength-selecting section 614, and the third group of through-holes 610 is filled with a third wavelength-selecting section 900. The third wavelength-selecting section 900 is, for example, a resin that transmits only light in a third wavelength band (e.g., 535 nm to 575 nm, centered around 555 nm). This allows three or more types of information to be acquired.

[0084] Furthermore, the through-hole 610 may correspond to one or more pixels PX. For example, as shown in Fig. 9(a), a plurality of through-holes 610 (four in Figs. 9(a) and 9(b)) may be provided for each pixel PX.

[0085] Furthermore, the through holes 610 belonging to the first group and the through holes 610 belonging to the second group may each correspond to a group area PAG. For example, the through holes 610 belonging to the first group arranged in four rows and four columns as shown in FIG. 9B may correspond to one group area PAG. Similarly, the through holes 610 belonging to the second and third groups arranged in four rows and four columns may each correspond to one group area PAG.

[0086] Furthermore, the through holes 610 belonging to the first group and the through holes 610 belonging to the second group may have different sizes. For example, of the through holes 610 belonging to the first group and the through holes 610 belonging to the second group, the diameter of the through hole 610 filled with a wavelength selection portion having a higher sensitivity may be smaller than the diameter of the other through hole 610. Furthermore, the sensitivity of the optical sensors 30 corresponding to the through holes 610 belonging to the first group and the through holes 610 belonging to the second group may be made different. This makes it possible to homogenize the intensity of the first detection signal Vdet corresponding to the through holes 610 belonging to the first group and the through holes 610 belonging to the second group.

[0087] As described above, an optical sensor having the first wavelength selection unit 612 and the second wavelength selection unit 614 can acquire multiple types of information using multiple wavelengths in a short period of time. It should be noted that even in conventional technology, multiple types of information about a measurement object can be acquired by sequentially irradiating the measurement object with light in multiple wavelength bands at intervals and sensing the reflected light and transmitted light from the measurement object. However, according to the present disclosure, multiple types of information can be acquired using multiple wavelengths in a short period of time.

[0088] 10(a) is a diagram showing the change in sensor output over time in the conventional technology (time division), and FIG. 10(b) is a diagram showing the change in sensor output over time in the present disclosure. The vertical axis of FIG. 10(a) and FIG. 10(b) represents the sensor output Vo, and the horizontal axis represents time. Here, it is assumed that the coordinate extraction unit 46 outputs the first detection signal Vdet as the sensor output Vo.

[0089] As shown in FIG. 10(a), according to the prior art, an LED emitting 850 nm light and an LED emitting 660 nm light are alternately illuminated. The sensor output Vo begins to increase as the LED is turned on, increases to a certain voltage corresponding to the amount of light emitted by the LED, and then stabilizes. The sensor outputs Vo output from all partial detection areas PAA are then acquired once (or a predetermined number of times). The power supply circuit 28 then switches the LEDs off when the reference signal COM is supplied to the additional capacitances Cad (see FIG. 4) included in the partial detection areas PAA.

[0090] When the LED is turned off, the sensor output Vo gradually decreases and, after a certain time, returns to the initial output voltage value (e.g., 0 V). To acquire multiple types of information, it is necessary to avoid mixing the sensor outputs Vo due to 850 nm light and 660 nm light. Therefore, a certain amount of time is required after the LED emitting 850 nm light is turned off to turn on the LED emitting 660 nm light. Similarly, a certain amount of time is required after the LED emitting 660 nm light is turned off to turn on the LED emitting 850 nm light. Therefore, according to the prior art, it takes time to switch between LEDs.

[0091] 10(b), even if an LED emitting light of 660 nm and an LED emitting light of 850 nm are simultaneously always turned on, multiple types of information can be obtained based on the sensor output Vo of the pixel PX corresponding to the first wavelength selection unit 612 and the sensor output Vo of the pixel PX corresponding to the second wavelength selection unit 614. Therefore, the detection accuracy per unit time can be improved.

[0092] Furthermore, by using an LED (for example, a white LED) that emits both 660 nm and 850 nm light, it is not necessary to provide LEDs that emit light of individual wavelengths.

[0093] Second Embodiment Next, a second embodiment will be described. Descriptions of the same configuration as in the first embodiment will be omitted. Fig. 11(a) is a schematic diagram showing a cross section of the optical sensor 1 according to the second embodiment. Fig. 11(b) is a schematic diagram showing a plan view of the optical sensor 1 according to the second embodiment. According to the second embodiment, a plurality of pixels and a plurality of through-holes 610 are arranged in a matrix, and through-holes 610 belonging to the second group are arranged on all four sides of each of the through-holes 610 belonging to the first group.

[0094] Specifically, the through holes 610 belonging to the first group and the through holes 610 belonging to the second group are alternately arranged in each column. Furthermore, the through holes 610 belonging to the first group and the through holes 610 belonging to the second group are alternately arranged in each row. That is, in a plan view, the through holes 610 belonging to the first group and the through holes 610 belonging to the second group are arranged in a checkerboard pattern.

[0095] FIG. 12 is a diagram illustrating a manufacturing method of an interposer 600 according to the second embodiment. First, a light-shielding film corresponding to the size of the detection area DA is prepared. Then, through-holes 610 are formed in positions that will overlap with each pixel PX of the light-shielding film when the light-shielding film is placed on the sensor unit 602. At this time, only the through-holes 610 belonging to the first group are formed. Next, the through-holes 610 belonging to the first group are filled with a resin that will become the first wavelength selection section 612. Next, a through-hole 610 belonging to the second group is formed at a position midway between adjacent through-holes 610 belonging to the first group. Finally, the through-holes 610 belonging to the second group are filled with a resin that will become the second wavelength selection section 614. Through the above steps, the interposer 600 according to the second embodiment is completed. Note that the process of filling the resin that will become the first wavelength selection section 612 and the process of forming the through-holes 610 belonging to the second group may be interchanged.

[0096] In the second embodiment, similarly to the first embodiment, multiple types of information can be obtained using multiple wavelengths in a short period of time.

[0097] Third Embodiment Next, a third embodiment will be described. Descriptions of the same configuration as in the first embodiment will be omitted. FIG. 13(a) is a schematic diagram showing a cross section of the optical sensor 1 according to the third embodiment. FIG. 13(b) is a schematic diagram showing the top surface of the optical sensor 1 according to the third embodiment. According to the third embodiment, the optical sensor 1 further includes a cover member 1300 that is disposed above the interposer 600 and covers the interposer 600, and the multiple wavelength selection units are formed as a light-transmitting adhesive film that bonds the interposer 600 and the cover member 1300 together.

[0098] 13(a) and 13(b), the through-hole 610 is filled with a resin that transmits light in the entire wavelength range of visible light (i.e., a transparent resin), or the through-hole 610 may be left unfilled (i.e., air is present).

[0099] A first wavelength selection section 612, a second wavelength selection section 614, and a third wavelength selection section 900 are disposed on the interposer 600. Specifically, a first adhesive film 604 that transmits only light in a first wavelength band (e.g., 640 nm to 680 nm with a center at 660 nm) is disposed on the first and second rows of through-holes 610 as the first wavelength selection section 612. A second adhesive film 606 that transmits only light in a second wavelength band (e.g., 830 nm to 870 nm with a center at 850 nm) is disposed on the third and fourth rows of through-holes 610 as the second wavelength selection section 614. A third adhesive film that transmits only light in a third wavelength band (e.g., 340 nm to 380 nm with a center at 360 nm) is disposed on the fifth and sixth rows of through-holes 610 as the third wavelength selection section 900.

[0100] In the third embodiment, similarly to the first embodiment, multiple types of information can be acquired using multiple wavelengths in a short time. According to the third embodiment, although the optical sensor is slightly thicker than in the first and second embodiments, the process of filling the through-hole 610 can be omitted, and therefore the manufacturing process can be simplified.

[0101] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations shown in the above-described embodiment can be replaced with configurations that are substantially the same as those shown in the above-described embodiment, that have the same effects, or that can achieve the same purpose.

[0102] Within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, to the above-described embodiments, a person skilled in the art may appropriately add, delete, or modify components, or add, omit, or change conditions of steps, and these modifications are also included within the scope of the present invention as long as they maintain the gist of the present invention.

Claims

1. a light receiving unit including a plurality of pixels arranged on a plane and configured to receive light from the object to be measured; an interposer having a plurality of through holes and arranged above the light receiving unit such that one or more of the through holes overlap with each of the pixels; a first wavelength selection unit formed of a resin that transmits only light in a first wavelength band and provided so as to overlap with the through holes belonging to a first group among the plurality of through holes; a second wavelength selection unit formed of a resin that transmits only light of a second wavelength band different from the first wavelength band, and provided to overlap with one of the plurality of through holes that belongs to a second group different from the first group; An optical sensor including:

2. The optical sensor according to claim 1 , wherein the first wavelength selection section and the second wavelength selection section are disposed inside the through-hole.

3. the plurality of pixels and the plurality of through-holes are arranged in a matrix, The first group and the second group are arranged side by side in a plane.

3. The optical sensor according to claim 2.

4. the plurality of pixels and the plurality of through-holes are arranged in a matrix, the through holes belonging to the second group are arranged on all four sides of each of the through holes belonging to the first group; 3. The optical sensor according to claim 2.

5. a cover member disposed above the interposer and covering the interposer; the first wavelength selection unit and the second wavelength selection unit are formed as a light-transmitting adhesive film that bonds the interposer and the cover member; 2. The optical sensor according to claim 1.

6. The size of the openings of the plurality of through holes on the light receiving unit side is smaller than the size of the openings on the opposite side.

2. The optical sensor according to claim 1.

7. Each of a plurality of first pixels included in the plurality of pixels overlaps with two or more of the plurality of through holes belonging to the first group, 2. The optical sensor according to claim 1, wherein each of a plurality of second pixels included in the plurality of pixels overlaps with two or more of the plurality of through-holes that belong to the second group.

8. The plurality of pixels and the plurality of through holes are respectively arranged in a matrix, the through holes belonging to the first group and the through holes belonging to the second group are alternately arranged in a first direction, 3. The optical sensor according to claim 2, wherein the through-holes belonging to the first group and the through-holes belonging to the second group are arranged alternately in a second direction intersecting the first direction.